Quantitative Mapping of T2 Using Partial Spoiling

Fast quantitative MRI has become an important tool for biochemical characterization of tissue beyond conventional T-1, T-2, and T-2(star)-weighted imaging. As a result, steady-state free precession (SSFP) techniques have attracted increased interest, and several methods have been developed for rapid quantification of relaxation times using steady-state free precession. In this work, a new and fast approach for T-2 mapping is introduced based on partial RF spoiling of nonbalanced steady-state free precession. The new T-2 mapping technique is evaluated and optimized from simulations, and in vivo results are presented for human brain at 1.5 T and for human articular cartilage at 3.0 T. The range of T-2 for gray and white matter was from 60 msec (for the corpus callosum) to 100 msec (for cortical gray matter). For cartilage, spatial variation in T-2 was observed between deep (34 msec) and superficial (48 msec) layers, as well as between tibial (33 msec), femoral, (54 msec) and patellar (43 msec) cartilage. Excellent correspondence between T-2 values derived from partially spoiled SSFP scans and the ones found with a reference multicontrast spin-echo technique is observed, corroborating the accuracy of the new method for proper T-2 mapping. Finally, the feasibility of a fast high-resolution quantitative partially spoiled SSFP T-2 scan is demonstrated at 7.0 T for human patellar cartilage. Magn Reson Med 66:410-418, 2011. (C) 2011 Wiley-Liss, Inc.